Mycotoxins are toxic secondary metabolites of fungi belonging, essentially, to the Aspergillus, Penicillium and Fusarium genera. They can be produced on a wide range of agricultural commodities and under a diverse range of agronomic, ecological and post harvest conditions worldwide.
Mycotoxins can enter the food chain in the field, during storage of a feed or food material, or at later points in the food chain. Their accumulation in foods and feeds represents a major threat to human and animal health since consumption of a mycotoxin-contaminated diet may result in teratogenic, carcinogenic and oestrogenic or immunosuppressive effects.
In 1985 the World Health Organization estimated that approximately 25% of the world's grains were contaminated by mycotoxins (Jelinek et al., 1989). This figure has likely grown since then due to an increase in global import and export of grains and cereals and the changing environmental and weather patterns.
Currently there are more than 400 mycotoxins documented but the mycotoxins of greatest concern and consequently the most studied include: aflatoxin, deoxynivalenol, zearalenone, fumonisin and ochratoxin.
Although there are many species of toxigenic moulds, only a few mycotoxins are considered to be significant for humans.
Three genera of fungi, Aspergillus, Penicillium, and Fusarium are most frequently involved with cases of mycotoxin contamination. Fungal colonization, growth and mycotoxin production are generally influenced by a variety of factors. The most important of which are temperature and water activity.
Generally, in warm regions aflatoxins are of major concern. This is because the Aspergillus species that produce these toxins find optimum conditions present in tropical regions. In contrast, Fusarium and Penicillium species have lower optimum temperatures and as a result are adapted to a more moderate climate. Ochratoxins, fumonisins and zearalenone are consequently produced in regions providing these conditions.
Ochratoxins are a group of mycotoxins produced as secondary metabolites by several fungi of the Aspergillus or Penicillium families and are weak organic acids consisting of a derivative of an isocoumarin. There are three generally recognized ochratoxins, designated A, B and C. Ochratoxin A is the most abundant member of the ochratoxin family and hence the most commonly detected, but is also the most toxic. Ochratoxin A (ochratoxin A) is a nephrotoxic, teratogenic, hepatotoxic, and carcinogenic mycotoxin present in cereals and other starch rich foods. Besides cereals and cereal products, ochratoxin A is also found in a range of other food commodities, including coffee, cocoa, wine, beer, pulses, spices, dried fruits, grape juice, pig kidney and other meat and meat products of non-ruminant animals exposed to feedstuffs contaminated with this mycotoxin. Many countries have set limits on ochratoxin A level in food, typically between 1 and 10 ppb (parts per billion) depending on the type and quality of the foodstuffs.
ochratoxin A production is due to a fungal infection in crops, in the field during growth, at harvest, in storage and in shipment under favourable environmental conditions, especially when they are not properly dried.
Ochratoxin A is a stable compound that can be hydrolysed into ochratoxin α (OTα) and L-phenylalanine by heating under reflux for 48 h in 6M hydrochloric acid (Van der Merwe et al., 1965) or with the carboxypeptidase A (Pitout, 1969). The conversion of OTA into ochratoxin α is considered to be a way to reduce its toxicity since OTα is commonly reported to be much less toxic than OTA. Moreover, ochratoxin α elimination half-time in the body (9.6 h) is shorter than that of OTA (103 h) (Li et al., 1997).

In order to ensure food safety, different approaches to prevent mycotoxin intake are developed at several stages along the food production chain.
It has been known since the 1970s that the mammalian digestive enzyme called carboxypeptidase A is cable of degrading OTA but that the efficiency of this enzyme is low. In fact in animals having carboxypeptidase A, such as pig, OTA toxicity due to its presence in feed is a problem. Furthermore, it has been found that OTA can to some extent inhibit carboxypeptidase A activity.
Prior to the present invention, there has been no disclosure of efficient enzyme solutions to degrade ochratoxins including ochratoxin A (OTA). Enzyme activities other than carboxypeptidase have been reported for OTA degradation, but until now no one has been able to identify a protein showing OTA degrading activity.
It is known that a commercial lipase product called “Amano™ lipase” which is a crude lipase produced from A. niger (Amano™ company, Japan) has ochratoxin degrading activity.
The OTA degrading activity in this lipase product has previously been attributed to a lipase or protease activity. For example, Maria A. Stander (J. Agric. Food Chem, 2000, 48, 5736-5739) concluded that the OTA degrading activity of Amano™ lipase resulted from a lipase.
Abrunhosa et al., (Biotechnology Lett., 2007, 29, 1909-1914) describe an enzyme preparation isolated from A. niger having OTA degrading activity. However, this enzyme preparation was not purified to an extent where the sequence of the active component could be determined at the amino acid or DNA level. Similar problems have been reported in other cases (Abrunhosa et al., TOXINS, [2010], 2, 1078-1099)